Tube OP-AMP ? for the DIYers

vapochilled · #1 09-16-2008, 10:45 PM

I just wonder. If any one has built and/or used a tube OPamp in their project(s)? I've seen several schematics for them, most 2 tubes per channel.

bongomania · #2 09-16-2008, 10:49 PM

While I haven't tried anything like that, I'm intrigued. Partly just techie curiosity, but partly because my main compressor has a hot-swappable opamp socket, I'd love to try a tube opamp in there.

mikeboth · #3 09-16-2008, 11:36 PM

roflol · #4 09-17-2008, 08:47 AM

Quote:

Originally Posted by unbeliever

unfortunatly if you use tubes they do actually sound better, if thats the sound your going for.

bongomania · #5 09-17-2008, 08:56 AM

mikeboth · #6 09-17-2008, 08:58 AM

Quote:

Originally Posted by roflol

unfortunatly if you use tubes they do actually sound better, if thats the sound your going for.

And if you're not, they don't? Gotcha.

RGs picture was showing what it *might* look like to try and get a tube into an IC socket. Obviously the humour failed.

vapochilled · #7 09-17-2008, 09:13 AM

Quote:

Originally Posted by bongomania

While I haven't tried anything like that, I'm intrigued. Partly just techie curiosity, but partly because my main compressor has a hot-swappable opamp socket, I'd love to try a tube opamp in there.

I am in the same boat. Quite intrigued. I know there are Pin adapters to convert SOICs to DIPs (I saw these in the digikey catalog). The signal leads from the tube opamp could be soldered to the Pin converter. To make the pin out swapping as easy as ICs, then it's just where to mount the tubes, and/or make a new case.

In way that beomes a modular "solid state to tube converter" I've been thinking it might be a cool way to to change tone, especially on any diy or kits. Where the end user wasn't satisfied with the tone.

Also I know there are some die hard tube guys that steer clear of solid state. These may offer a tube alternative to modern effects.

Ubeleiver - I love the pic, lol.

lowmid · #8 09-17-2008, 11:00 AM

tube op amp??? a typical opamp contains about 10 transistors and one tube is supposed to have the same effect as one transistor, so that means something like 5 12AX7 (they are dual triodes) to replace each transistor in favor for a tube??

am I missing something?

metalmariachi · #9 09-17-2008, 11:32 AM

It depends on the op amp.
A 4558 contains 2 op amps, in essence it could be replaced with a 12AX7.
The down side of conversion is operating voltages as well as little things like cathode bias resisters and bypass caps.

Why don't you just use one of the many amp schematics? essentially your building a preamp so you can go from a very simple Volume tone set up to cascading gain stages and tone set ups like the Oliver amps with controls for ultra high, ultra low, low mids and high mids.

MM

seanm · #10 09-17-2008, 11:46 AM

I think it would be much much much easier to design a tube based effect than try to build a "tube opamp" to fit in an existing effect.

bongomania · #11 09-17-2008, 12:08 PM

Yeah, sure, but who cares about "easy"? We want a challenge, especially one which will make other geeks say "oooh aaaaahh!"

Jonyak · #12 09-17-2008, 12:18 PM

you would need a separate pedal with a separate supply voltage and wires going into the pin slots just to do this. interesting idea, not very practical.

seanm · #13 09-17-2008, 12:38 PM

Quote:

Originally Posted by bongomania

Yeah, sure, but who cares about "easy"? We want a challenge, especially one which will make other geeks say "oooh aaaaahh!"

Nahhhh.... I've seen a tube op-amp so it's no longer cool

And they are big... the opamp will be much larger than the effect which really reduces the cool factor.

runmikeyrun · #14 09-17-2008, 01:54 PM

Quote:

Originally Posted by roflol

unfortunatly if you use tubes they do actually sound better, if thats the sound your going for.

A poorly designed tube circuit will sound worse than a well designed SS circuit. Just throwing a tube in something won't necessarily make it sound better. Case in point- we recorded a 4 song EP years back at a studio. I used a budda zenman distortion pedal at the time with 2 really nice NOS Mullards in it. Well it was stolen and i replaced with with a Boss DS-1. Went back in to record a full length and the engineer said "wow, what did you do with your sound? It's way better". I thought that tube pedal killed it but when i compared the two tones after the album was finished it was night and day. I joke saying the thief did me a $200 favor

Now a well designed tube circuit... depending on your taste and application... can sound WAY better!

If you're into modding pedals check out the guy's page who made that pic (R.G.) he is the MAN with electronics.

roflol · #15 09-17-2008, 05:50 PM

Quote:

Originally Posted by runmikeyrun

A poorly designed tube circuit will sound worse than a well designed SS circuit. Just throwing a tube in something won't necessarily make it sound better. Case in point- we recorded a 4 song EP years back at a studio. I used a budda zenman distortion pedal at the time with 2 really nice NOS Mullards in it. Well it was stolen and i replaced with with a Boss DS-1. Went back in to record a full length and the engineer said "wow, what did you do with your sound? It's way better". I thought that tube pedal killed it but when i compared the two tones after the album was finished it was night and day. I joke saying the thief did me a $200 favor

Now a well designed tube circuit... depending on your taste and application... can sound WAY better!

If you're into modding pedals check out the guy's page who made that pic (R.G.) he is the MAN with electronics.

it's all down to preference i prefer to have my original tone cut through rather than a pedal colour my tone beyond recognition. but obviously a **** pedal is going to sound worse than a good one.

bongomania · #16 09-17-2008, 06:05 PM

So you think a tube amp is your "original tone" cutting through?

Srsly, you'll want to do some studying about how your equipment actually works before making these pronouncements about how tubes sound.

Edit: also you ignored the whole point of his story which was that in that instance a "****" pedal actually sounded a lot better in the mix than the expensive boutique one.

roflol · #17 09-18-2008, 04:56 AM

Quote:

Originally Posted by bongomania

So you think a tube amp is your "original tone" cutting through?

Srsly, you'll want to do some studying about how your equipment actually works before making these pronouncements about how tubes sound.

Edit: also you ignored the whole point of his story which was that in that instance a "****" pedal actually sounded a lot better in the mix than the expensive boutique one.